Field of the Invention
The present invention relates to a transfer-type image recording method using a treatment liquid and an ink.
Description of the Related Art
As an image recording method using an ink, a transfer-type image recording method has been known. By the method, an ink is applied to an image formation surface of an intermediate transfer member to form an intermediate image, and the intermediate image is transferred to a recording medium.
In the transfer-type image recording method, the fixation of an intermediate image formed with an ink proceeds on an intermediate transfer member, and thus the method enables stable image formation even when a recording medium having low ink absorbability or a recording medium having a small ink absorption capacity is used. For example, when a thin paper having a small water absorption capacity used in the commercial printing field is used to record an image by an ink jet method, damages such as cockling and curling may be caused to the paper itself. Even for such a thin paper, when the fixation of an intermediate image is allowed to proceed on an intermediate transfer member and then the image is transferred to the thin paper, the image in which the generation of cockling or curling is suppressed can be recorded.
In the transfer-type image recording method, an image recording method using two liquids of a treatment liquid and an ink has been known. The treatment liquid has a function of causing aggregation of components contained in an ink. Application of the treatment liquid causes aggregation of the ink applied to an intermediate transfer member to promote the fixation of an intermediate image.
As for typical coating of a treatment liquid, the whole of an ink image as an intermediate image formed by application of ink drops on an intermediate transfer member, that is, an area larger than the size of an ink image is preferably coated with a treatment liquid in order to certainly achieve the aggregation effect to the margin of the ink image. In this case, the treatment liquid coating film formed on an intermediate transfer member includes an area where the treatment liquid comes in contact or is mixed with the film of an ink and reacts with the ink to increase the viscosity and an area where the treatment liquid does not come in contact with the ink film and does not contribute to the viscosity increasing reaction. The area having a higher viscosity forms an intermediate image, which is transferred to a recording medium. At the time of transfer, most of the area that does not come in contact with the ink film and does not contribute the viscosity increasing reaction is not transferred to a recording medium and is left on the intermediate transfer member.
When an intermediate transfer member is reused (in other words, an intermediate image is transferred from an intermediate transfer member to a recording medium, and then another intermediate image is formed once again on the intermediate transfer member after the transfer), the surface of the intermediate transfer member after the transfer of an intermediate image is cleaned to remove the remainders such as a treatment liquid left on the intermediate transfer member. However, if a treatment liquid having high wettability with respect to an intermediate transfer member is used, the treatment liquid cannot be completely removed even by cleaning in some cases. If an intermediate transfer member on which a treatment liquid is left is coated with the treatment liquid once again, the coating state of the treatment liquid becomes uneven, and thus the treatment liquid coating film formed on the intermediate transfer member have various thicknesses in some cases. Such a variation in the thickness of the treatment liquid coating film causes a variation in the size of dots formed from ink drops applied to the treatment liquid coating film, and affects precise formation of an intermediate image, in some cases.
As measures against the above-described problem relating to cleaning, Japanese Patent Application Laid-Open No. 2009-51118 discloses an ink jet recording method in which on an intermediate transfer member a first release agent, a second release agent as a treatment liquid, and ink dots are applied in this order to form an image and a cleaning step after image transfer is performed in the following conditions.Cleaning temperature>Tg of first release agent>transfer temperature>Tg of second release agent
In Japanese Patent Application Laid-Open No. 2009-51118, the temperature is controlled in such a way that only the second release agent becomes in a flowable state at the time of transfer and then the first release agent layer also becomes in a flowable state at the time of cleaning. On this account, by removing the first release agent layer from the intermediate transfer member at the time of cleaning, the reaction liquid and the ink can be removed together with the first release agent layer even if left on the first release agent layer, and thus insufficient cleaning can be suppressed according to this method.